I would go after NOS Rebuild kits and supplement them with modern rubber (ethanol impervious) parts where needed (e.g. accelerator pump). The folks over at Mike's Carburetor Parts have these individual bits.

Personally, I have several OEM rebuilds kits on hand should the need arise. Moreover, I am not expecting problems with the Carter WCD and ethanol because there is no rubber whatsoever. The accelerator pump is actually leather.